Home The 11 Best Humidifiers of 2023, Tested and Reviewed We tested 38 humidifiers and found the best options to combat allergies, asthma, dry skin, and more. By Melanie Fincher Melanie Fincher Melanie Fincher is the associate commerce editor for Real Simple and has over three years of experience writing product reviews and lifestyle content. She was the former SEO writer for Allrecipes, covering product reviews, cooking tutorials, and food news. Real Simple's Editorial Guidelines Updated on March 22, 2023 Share Tweet Pin Email In This Article Expand Jump to a Section Our top picks Reviews Final Verdict Our Testing Process How to Shop More to Consider FAQs Take Our Word for It What Is Real Simple Selects? We independently evaluate all recommended products and services. If you click on links we provide, we may receive compensation. Learn more. Real Simple / Dera Burreson When the humidity drops too high or too low, it can contribute to asthma, allergies, dry skin, and more, which is why managing the moisture levels in your home is so important to improve air quality. A humidifier helps to keep an optimal humidity level in your home, and can even provide a better night’s rest by improving sleeping conditions for adults and babies alike. “The Environmental Protection Agency (EPA) recommends that indoor humidity be in the range of 30 to 50 percent,” says Melanie Carver, chief mission officer at the Asthma and Allergy Foundation of America (AAFA). “If the humidity levels in your home are too low (less than 30 percent), you can add moisture by using a humidifier. Humidifiers produce water vapor or steam to introduce moisture into the indoor environment.” We tested 38 of the best humidifiers in our Lab and in our homes, evaluating them on effectiveness, noise level, design, size, ease of cleaning, and overall value. We also spoke with Carver to learn about the effects of humidity on asthma and allergies, as well as what features to look for in a humidifier. Our Top Picks Best Overall Ultrasonic Humidifier: Honeywell Designer Series Humidifier at Amazon Jump to Review Best Overall Evaporative Humidifier: Honeywell Cool Moisture Humidifier at Amazon Jump to Review Best Budget Humidifier: Magictec Cool Mist Humidifier at Amazon Jump to Review Best Splurge Humidifier: Dyson Purifier Humidify + Cool Autoreact at Walmart Jump to Review Best Humidifier for Bedrooms: Crane Ultrasonic Cool Mist Humidifier at Amazon Jump to Review Best Humidifier for Large Rooms: Lacidoll Cool Mist Ultrasonic Whole House Humidifier at Amazon Jump to Review Best Warm and Cool Mist Humidifier: Vicks Dual Comfort Cool Warm Mist Humidifier at Amazon Jump to Review Best Portable Humidifier: Geniani Cool Mist Humidifier at Amazon Jump to Review Best Quiet Humidifier: Everlasting Comfort Cool Mist Humidifier at Amazon Jump to Review Best Smart Humidifier: Levoit Classic Smart Humidifier at Amazon Jump to Review Best Overall Ultrasonic Humidifier Honeywell Designer Series Cool Mist Humidifier 4.8 Amazon View On Amazon View On Honeywellpluggedin.com Our Ratings Setup 5/5 Effectiveness 5/5 Design 5/5 Size 4/5 Ease of Cleaning 4/5 Who it’s for: People who want a quiet and easy-to-use humidifier with a streamlined look. Who it isn’t for: People who want a humidifier that does not produce a visible vapor cloud. This sleek and simple humidifier received high marks across the board in our testing. It uses filter-free, ultrasonic technology to release a cool mist, which was visible the instant we turned it on. The easy-to-use, adjustable mist control allows you to change the output depending on your preference. After six months of use, it has helped to alleviate dry winter skin, plus we found it to be extremely quiet, with only some low bubbling noise. Special features include an auto shut-off that turns the machine off when the water runs out, a refill light, and an essential oil tray if you want to use it as a diffuser. We love the sleek design of this unit, which hides the tank while still providing an illuminated water window so you can check how full it is. The compact, vertical shape doesn’t take up much space, making this a great option for a nightstand or side table. Plus, the handle that runs the length of the tank makes it easy to carry from the sink back to the base. In terms of setup and maintenance, this unit requires no assembly, and is very easy to fill and clean thanks to its large, round tank (although it’s not dishwasher-safe). This is really a no-frills machine—it doesn’t have any smart features or a digital display, but its simple design and ultra-quiet operation make it one of the best cool mist humidifiers for a mid-sized room, such as a bedroom. And after six months of using this humidifier while sleeping, we are happy to report that it remains just as quiet as ever. Price at time of publish: $74 Type: Ultrasonic | Size: 8.8 x 8.8 x 13.2 inches | Weight: 6.6 pounds | Water Tank Capacity: 1.25 gallons | Run Time: Up to 24 hours | Essential Oil Tray: Yes Real Simple / Dera Burreson Best Overall Evaporative Humidifier Honeywell Cool Moisture Humidifier 4.8 Amazon View On Amazon View On Walmart View On Honeywellpluggedin.com Our Ratings Setup 5/5 Effectiveness 5/5 Design 5/5 Ease of Cleaning 4.5/5 Value 3/5 Who it’s for: People who want a fast-acting humidifier that doesn't produce a visible mist. Who it isn’t for: People who don’t want to worry about regularly replacing a filter. Evaporative humidifiers use a fan to pull in air and blow it through a wick filter, which causes the water in the tank to evaporate quickly and turn into water vapor. This water vapor is then released into the air in the form of an ultra-fine, nearly undetectable mist. Our favorite evaporative humidifier, the Honeywell Cool Moisture Humidifier, increased the humidity by an average of 33 percent on the highest setting and 24 percent on the lowest setting in eight hours, all without creating any visible mist. And because it has a filter, it won’t disperse minerals commonly found in tap water into the air. Just keep in mind that the filter will require replacement every 30-60 days, depending on whether you have hard or soft water. Because evaporative humidifiers require an internal fan to run, they’re usually louder than their ultrasonic counterparts. Fortunately, we found this evaporative humidifier to be both effective and quiet, so much so that we’d even recommend it for use in the bedroom or in a nursery, particularly when used on the lowest setting. Furthemore, the transparent tank was easy to remove and fill, and the 1.1-gallon capacity can run for up to 24 hours without needing a refill. Plus, all the parts that come in contact with water are dishwasher-safe, making it a breeze to sanitize. Price at time of publish: $80 Type: Evaporative | Size: 17.9 x 9.37 x 11.4 inches | Weight: 8.4 pounds | Water Tank Capacity: 1.1 gallons | Run Time: Up to 24 hours | Essential Oil Tray: No Best Budget Humidifier Magictec Cool Mist Humidifier 4.3 Amazon View On Amazon Our Ratings Setup 5/5 Effectiveness 5/5 Design 4/5 Size 4/5 Ease of Cleaning 3/5 Who it’s for: People who want an affordable and compact humidifier that will blend into its surroundings. Who it isn’t for: People who don’t want to use a brush to clean the tank. Immediately upon turning on this humidifier, a visible mist appeared and the white indicator light switched on to signal that the machine was in use. The ultrasonic operation was practically silent, and there was no leaking or puddling. We particularly loved the nozzle sprayer attachment that allows you to direct the flow of the mist to where it’s most needed. The indicator light turns red and the unit goes into standby mode when the water is running low. Once it has run out of water entirely, it automatically shuts off. Despite the fact that it's compact enough to slide onto a shelf or side table, this humidifier has an impressive 24-hour run time. We found the setup to be very easy; however, cleanup proved a little more difficult. The reservoir’s opening wasn’t big enough to fit our hands, so it required a brush to clean it out. Although this humidifier doesn’t feature fancy extras like a digital display, smart device compatibility, or a humidistat, it still outperformed many higher-priced models in terms of effectiveness and design. Over time, the humidifier has helped in alleviating dry skin and sinus problems, although we have noticed a bit of a ripe smell coming from the tank, so regular cleaning is a must. If you’re looking for an inexpensive humidifier that can blend into small to medium spaces while still delivering powerful results, this one more than fits the bill. Price at time of publish: $22 Type: Ultrasonic | Size: 7.8 x 7.8 x 11.8 inches | Weight: 2.35 pounds | Water Tank Capacity: 85 ounces | Run Time: Up to 24 hours | Essential Oil Tray: No Real Simple / Dera Burreson Best Splurge Humidifier Dyson Purifier Humidify + Cool Autoreact 4.8 Best Buy View On Walmart View On Wayfair View On Target Our Ratings Setup 4.5/5 Effectiveness 5/5 Design 4/5 Ease of Cleaning 5/5 Value 4/5 Who it’s for: People willing to splurge on a three-in-one humidifier that also acts as a fan and air purifier. Who it isn’t for: People who want a tabletop humidifier and people who only use humidifiers seasonally. With the name Dyson attached to it, you know it’s going to be a multifunctional and sleek device with many advanced features—and that's exactly what the Purifier Humidify + Cool Autoreact is. This three-in-one unit releases clean, humidified air throughout the room to simultaneously purify, humidify, and cool (or you can go without cooling by setting it to the Backwards Airflow setting, which directs airflow through the back of the unit). After eight hours of continuous running, it was able to increase the humidity of our space by an average of 8.4 percent on the lowest setting and 18 percent on the highest setting. This isn’t as high as some of the lesser priced models on our list, but to be fair, those models don’t double as fans or air purifiers. On auto mode, the humidifier automatically senses and reports the air quality and humidity level and adjusts accordingly, while the night mode runs on the quietest setting and dims the display so as to not disturb sleep. We particularly like the oscillation, which circulates the newly purified and humidified air throughout a large room. Do keep in mind that this unit stands three feet tall, meaning it's best suited for larger rooms where it can be kept on the floor. Dyson also manages to make cleanup easy with an automated deep clean cycle that eliminates mineral buildup and odors. The 1-gallon tank can run for up to 36 hours without needing a refill and comes with tiny wheels so you can easily wheel it to and from the faucet—though we did have some trouble with the tank leaking once it was removed from the unit. It also comes with a remote that attaches to the main unit for storage. In short, this is an investment piece that replaces three appliances in one, but it may be overkill for anyone who only uses humidifiers seasonally or who doesn’t need the additional functionality. Price at time of publish: $800 Type: Evaporative | Size: 12.3 x 11 x 36.6 inches | Weight: 18 pounds | Water Tank Capacity: 1 gallon | Run Time: Up to 36 hours | Essential Oil Tray: No Best Humidifier for Bedrooms Crane 4-in-1 Drop Ultrasonic Cool Mist Humidifier EE-8086 4.4 Amazon View On Amazon View On Nordstrom View On Target Our Ratings Setup 5/5 Effectiveness 4.3/5 Design 4.8/5 Ease of Cleaning 4.3/5 Value 4/5 Who it’s for: People who want an effective humidifier that also works as a sound machine, night light, and diffuser. Who it isn’t for: People who want a humidifier that can be felt from a distance. This tabletop humidifier makes a great bedside companion for a number of reasons. In addition to adding moisture back into the air, it also features a sound machine with three calming options to choose from—ocean waves, rain, and white noise—as well as a color-changing nightlight. Plus, it comes with a bottom tray where you can place one of Crane’s calming essential oil pads or menthol vapor pads for soothing aromatherapy all night long. In eight hours, the Crane Drop 2.0 increased the humidity of our room by an average of 14 percent when used on the highest setting. Although, when we recorded the humidity level from 10 feet away (as opposed to two feet), it dropped to about eight percent, leading us to conclude that this humidifier is best kept close by, such as on a nightstand. Filling and cleanup are also super easy, thanks to the top-fill tank and detachable cord. The unit disassembles for easy cleaning, and the tank is free of nooks and crannies that would make it hard to clean (though the parts aren’t dishwasher-safe). Overall, we found this to be a simple and intuitive humidifier that offers some bonus features that make it perfect for bedside use. Price at time of publish: $65 Type: Ultrasonic | Size: 8.6 x 8.6 x 13.4 inches | Weight: 4.25 pounds | Water Tank Capacity: 1 gallon | Run Time: Up to 24 hours | Essential Oil Tray: Yes Best Humidifier for Large Rooms Lacidoll 4.2 Gal. Cool Mist Ultrasonic Whole House Humidifier 4.9 Amazon View On Amazon View On Walmart Our Ratings Setup 5/5 Effectiveness 5/5 Design 5/5 Ease of Cleaning 4.5/5 Value 5/5 Who it’s for: People who want a large humidifier they don’t have to refill often. Who it isn’t for: People who want a more discreet humidifier. The Lacidoll Cool Mist Ultrasonic Whole House Humidifier is ideal for large rooms and open floor plans. After eight hours of continuous use, this humidifier was able to increase the humidity by 36 percent on its highest setting, which is among the highest of all those we tested. The tank is the largest on our list at 4.2 gallons and can run for up to 48 hours without needing a refill, while the adjustable, 360-degree mist tube allows you to direct the mist to areas that might otherwise be out of reach. Because of this, we think that this would make a particularly great purchase for people with lots of indoor plants, especially if the plants are hanging or placed on a high shelf. Despite its size and impressive performance, this unit was relatively quiet on all settings. The large digital display is easy to read, and the unit comes with a remote that allows you to control the settings from up to 16 feet away. It also has a built-in humidistat that gives you a real-time reading of your humidity levels and an auto shut-off that kicks in once the unit runs out of water or is tipped over. The tank can be filled from the top without removing the cover, though you won’t have to fill it very often given its size. And finally, cleanup is easy thanks to the large reservoir that you can easily fit your hand into. Price at time of publish: $180 Type: Ultrasonic | Size: 11.2 x 11.2 x 27 inches | Weight: 7.3 pounds | Water Tank Capacity: 4.2 gallons | Run Time: Up to 48 hours | Essential Oil Tray: Yes Best Warm and Cool Mist Humidifier Vicks VWC775 Dual Comfort Cool Warm Mist 4.6 Amazon View On Amazon Our Ratings Setup 5/5 Effectiveness 4.7/5 Design 4.2/5 Ease of Cleaning 4.5/5 Value 5/5 Who it’s for: People who want a humidifier for year-round use. Who it isn’t for: People with pets or kids who want to avoid a humidifier with a heating element. Both warm and cool mist humidifiers are effective at adding moisture back into the air, but cool mist humidifiers can add a bit of a chill to the room, while warm mist humidifiers can keep you more comfortable during the colder months. Thus, a humidifier that offers both warm and cool mist is ideal for year-round use. We like the Vicks Dual Comfort humidifier, because it was able to increase the humidity level of the room by 40 percent after running it continuously on the highest setting for eight hours— although we did find there to be a large disparity between the highest and lowest settings, as the latter only increased the humidity by 7 percent after eight hours. Plus, it comes with dual rotating nozzles so you can direct the mist where it’s most needed. We didn’t have any issues with hot steam spurting from the unit, although we still recommend exercising caution with warm mist humidifiers, especially if you have kids or pets, because they do have a heating element. This humidifier can also be used in conjunction with Vicks VapoSteam or VapoPads to create a medicated steam for relieving cold symptoms. But do keep in mind that cleanup requires that you use the included brush (which is stored neatly under the tank) to get into the nooks and crannies. Price at time of publish: $99 Type: Ultrasonic (cool mist) | Size: 10.1 x 10.1 x 14.7 inches | Weight: 8 pounds | Water Tank Capacity: 1.2 gallons | Run Time: Up to 36 hours | Essential Oil Tray: Yes (can be added to medicine cup) Best Portable Humidifier Geniani Portable Small Cool Mist Humidifier 4.5 Amazon View On Amazon View On Walmart View On Geniani.com Our Ratings Setup 5/5 Effectiveness 4/5 Design 3/5 Size 5/5 Ease of Cleaning 5/5 Who it’s for: People who want an ultra-lightweight humidifier that can be taken on the go. Who it isn’t for: People who want to be able to control the mist output. This humidifier’s compact size and lighter weight allows it to go from the office to the home with ease. Plus, it’s small enough to fit in a cup holder and has a USB plug, so you can even use it in the car during the dry winter months. For one of our testers, this little humidifier was even powerful enough to put a stop to frequent nosebleeds and congestion. The cool mist begins to appear within a few seconds of turning on the humidifier. It features two different settings—one for continuous mist and one for intermittent mist, meaning 10 seconds on and 10 seconds off. It also features an auto shut-off setting for when the water runs out. Aside from the above features, this humidifier has very few adjustable settings, which can be a good or bad thing depending on your needs. The intuitive one-button control makes it a great choice for a guest bedroom or a car, but it also means that your control over the mist output is limited. We found this humidifier to be practically silent, and thanks to its eight-hour run time, you can keep it on your desk all day without it serving as a distraction—ideal if you suffer from excoriation. Setup and cleanup were both a breeze, since the small tank has a large, round opening that’s easy to clean without the use of a brush. If dry winter air has you wishing you could bring your humidifier with you everywhere, then this unit is your solution. Price at time of publish: $33 Type: Ultrasonic | Size: 2.6 x 4.9 x 3.7 inches | Weight: 10.8 ounces | Water Tank Capacity: 8.5 ounces | Run Time: Up to 8 hours | Essential Oil Tray: No Real Simple / Dera Burreson Best Quiet Humidifier Everlasting Comfort Ultrasonic Cool Mist Humidifier 4.6 Amazon View On Amazon View On Walmart Our Ratings Setup 5/5 Effectiveness 4.7/5 Design 4.4/5 Ease of Cleaning 4.8/5 Value 3/5 Who it’s for: People who are sensitive to sound and want a whisper-quiet humidifier. Who it isn’t for: People who want a humidifier with a top-fill tank. This humidifier stood out among all those we tested for its whisper-quiet operation that was nearly undetectable on the lowest setting. It even beat out much more expensive models when it came to noise level, making this a great choice if it will be running often, perhaps when using it to combat dust bunnies in your home.This is an ultrasonic humidifier, so it requires no filter maintenance and it produces a rather large vapor cloud. Given the size of the vapor cloud, it didn’t increase humidity levels quite as much as we were expecting (although a 23 percent increase after running for eight hours on the lowest setting is still nothing to sneer at). Additional features include an essential oil tray, an LED light that illuminates the amount of water left in the tank, as well as an auto shut-off feature that turns off the machine when the water level is low. And the 360-degree dual-mist nozzles pump the cool mist out of multiple directions for full-room coverage. This is a no-frills, basic humidifier that’s easy to adjust—simply turn the dial to adjust the mist output between high and low. Our major complaint with this humidifier is its refill and cleanup process—the design requires you to fully remove the tank from the electric base, turn it over, unscrew the canister opening, fill the tank either underneath a faucet or using a water pitcher, and then carry it back to the base while full. This process is somewhat laborious and messy, and those with grip strength challenges may want to choose another humidifier with a top-fill tank. The manufacturer recommends cleaning the tank once every 2-3 weeks (it comes with a brush for getting into the nooks and crannies), and the base about once per week. Price at time of publish: $70 Type: Ultrasonic | Size: 11.4 x 6.7 x 13.3 inches | Weight: 3 pounds | Water Tank Capacity: 1.6 gallons | Run Time: Up to 50 hours | Essential Oil Tray: Yes Best Smart Humidifier Levoit Classic 300S Ultrasonic Smart Humidifier 5 Amazon View On Amazon View On Walmart View On Target Our Ratings Setup 5/5 Effectiveness 5/5 Design 5/5 Size 5/5 Ease of Cleaning 5/5 Who it's for: People who want an adjustable humidifier with smart features. Who it isn't for: People who want a humidifier with basic controls. For large rooms up to 505 square feet, this humidifier emits a cool and refreshing mist for as long as 24 hours at a time. In our testing it was practically silent, and the mist appeared swiftly after touching the power button. Unlike other humidifiers, the Levoit 300S has plenty of customizable features, so you have maximum control over the humidity in your space. It features a digital display with a touchscreen power button, adjustable mist settings, an aromatherapy tray, an adjustable nozzle that allows you to change the direction of the mist, and an auto mode that uses a humidity sensor to adjust your mist to balance with your home's humidity. The digital display will even tell you the humidity level of the room at any given time. On top of all this, the humidifier features smart device compatibility: You can control it from the Vesync App, as well as Alexa and Google Assistant, which is great for those with a nursery who want to adjust the humidity from another room. Despite its large capacity, the top-fill water tank is still compact enough to fit under the bathroom faucet, and we found it easy to fill and transport—although it felt heavy when full, it has two indentations on the sides that act as handles, making transportation much easier and spill-free. Plus, we found both setup and cleanup to be very easy, thanks to the wide opening of the water tank. For all the extra features and smart capability you get with this humidifier, it's an unbeatable value. Price at time of publish: $80 Type: Ultrasonic | Size: 9.6 × 7.5 × 13.4 inches | Weight: 4.3 pounds | Water Tank Capacity: 1.6 gallons | Run Time: Up to 60 hours | Essential Oil Tray: Yes Real Simple / Dera Burreson Best Stylish Humidifier Vitruvi Cloud Cool Mist Humidifier 4.4 Nordstrom View On Amazon View On Nordstrom View On Bluemercury.com Our Ratings Setup 5/5 Effectiveness 4.5/5 Design 4.5/5 Ease of Cleaning 4.3/5 Value 3.5/5 Who it’s for: People who want an effective humidifier that will blend into its surroundings. Who it isn’t for: People who want a humidifier with a large tank that requires fewer refills. By far the best looking humidifier we’ve tested, the Vitruvi Cloud features a sleek, organically shaped design that seamlessly blends into its surroundings. But more importantly, it was able to increase the humidity by an average of 30 percent after running for eight hours on its highest setting. Use the touch-sensitive controls to choose between one of five mist levels, set a timer ranging from eight to 24 hours, or set it to night mode, which dims the display. We found the noise level to be consistent across all the mist levels, producing a quiet hum and trickling sound that was more soothing than disruptive (although those who are sensitive to any sound while sleeping may want to look elsewhere). The Cloud comes with a 360-degree rotating mist spout that helps the compact humidifier to reach more area. However, we would like to see a larger tank capacity for the price—at 20.3 ounces, this is the second smallest tank on our list only behind the Geniani Erie Portable Small Cool Mist Humidifier. Fortunately, the removable tank is dishwasher-safe, making it that much easier to sanitize. Despite the fact that this is an ultrasonic humidifier, it does come with a water filter to capture minerals commonly found in tap water, so you don’t need to worry about using distilled water. (Replacement filters retail for $30 for a 2-pack, and Vitruvi recommends you replace them every three months for best results.) Choose from three different neutral colors: white, oat, and dove (gray). Price at time of publish: $229 Type: Ultrasonic | Size: 3.7-4.7 x 10.7 x 8.5 inches | Weight: 3.5 pounds | Water Tank Capacity: 20.3 ounces | Run Time: Up to 24 hours | Essential Oil Tray: No Final Verdict Our best overall pick is the Honeywell Designer Series Cool Mist Humidifier, because it’s easy to use, features adjustable mist controls, and has a very quiet operation. Plus, its sleek design and compact size make it one of the best humidifiers for a mid-sized room, such as the bedroom. Real Simple / Dera Burreson Our Testing Process We put 38 of the best humidifiers through a series of tests both in our Lab and in our homes to determine which ones are worth buying. First, we evaluated the setup of each humidifier by timing how long it took to assemble straight out of the box. We also filled the water tank to capacity with distilled water, noting how heavy the tank was when full. Once the water tanks were full, we measured the effectiveness of each humidifier by running them continually for eight hours both on the highest and lowest setting and used a hygrometer to record the humidity level of the room before and after running the humidifier. We also took note of how loud each unit got, including whether it produced any humming, whistling, or crackling noises. Once the humidifiers were done running, we inspected the area around them to check for any visible puddling or leaking. We also evaluated the design and size of each humidifier, including whether it blends in well with its surroundings, how much room it takes up, whether the cord is long enough to reach the outlet, how user-friendly the display is, whether it includes any smart features, its water tank capacity, its run time, and more. After each use, we emptied and cleaned the tank, evaluating how easy it was to clean, including whether or not it’s dishwasher-safe. Finally, we rated the overall value of each humidifier, considering whether the performance justified the price. Once Lab testing was complete, we brought the humidifiers home and tested them over a period of 3-6 months, providing updates as to how well they held up to daily use. Real Simple / Dera Burreson How to Shop for Humidifiers Like a Pro Cool Mist vs. Warm Mist Most of the humidifiers we tested—and most on the market today—are cool mist humidifiers, meaning they release room-temperature mist into the air. They make a great choice for those with kids or pets, because there isn't a risk of burns in the event of a spill. Cool mist humidifiers are also more versatile because they can be used year-round without overheating your space during the warmer months. And because the water doesn't need to be heated, cool mist humidifiers typically use less energy, too. The best warm mist humidifiers are just as effective at humidifying air, but unlike cool mist humidifiers, they have an internal heating element that boils the water before releasing it. You may choose to go with a warm mist humidifier during the winter months as part of your winter skincare routine. Fortunately, you can find humidifiers with both cool and warm mist settings, such as the Vicks Dual Comfort Cool + Warm Mist Humidifier, our favorite humidifier with both warm and cool mist. Ultrasonic vs. Evaporative Depending on how they produce moisture, most cool mist humidifiers fall into one of two camps: ultrasonic or evaporative. Ultrasonic humidifiers produce a cool mist by using high-frequency sound vibrations from two ceramic plates. Evaporative humidifiers feature an internal fan that pulls in air and blows it through a wick filter, causing the water to evaporate and expel into the room in the form of a very fine, sometimes undetectable mist. Ultrasonic humidifiers tend to have a quieter operation (because there’s no internal fan), and they don’t have a filter to replace. However, they have more of a tendency to disperse contaminants into the air, such as minerals commonly found in tap water. You can combat this by using distilled water and regularly cleaning your humidifier. (Although, the Vitruvi Cloud Cool Mist Humidifier is an ultrasonic humidifier that comes with a water filter to trap contaminants found in tap water.) In general, ultrasonic humidifiers tend to be more expensive than their evaporative counterparts. Size and Capacity Different humidifiers are intended for different room sizes, with the tank size generally acting as an indicator of how much space a unit can humidify. In general, humidifiers for small to mid-sized rooms tend to hold less than about one gallon of water, while the best humidifiers for a large room will require a bigger tank capacity. Keep in mind that you may need to carry the tank to and from the sink to fill it, so you’ll want to be sure it’s comfortable to handle and not too heavy. You'll also want to consider whether you plan to move your humidifier from room to room, or keep it in one room at all times. If portability is a factor, consider the weight of the machine. Additionally, manufacturers will usually list the run time of a machine, which is an estimate of how often you'll need to refill the tank. This is closely related to the tank size and thus, the size of the room you'll be able to humidify. For humidifiers with longer run times, an auto shut-off setting can be helpful: These will either shut off the unit when it runs out of water, or use a humidistat to measure the room's humidity and then turn off the machine when the room reaches the desired level. Real Simple / Dera Burreson Noise A quiet humidifier will hover around 30 decibels, about as loud as a soft whisper, according to the CDC. Evaporative models tend to be louder than their ultrasonic counterparts because of their internal fan. If you’re purchasing a humidifier for a bedroom or nursery, you’ll want to keep this in mind when shopping. Cleanup Cleaning your humidifier at least once a week is imperative to prevent bacteria growth that can be expelled into the air. To make this process easier, look for a unit that's easy to disassemble and a water tank that's easy to clean. More Humidifiers to Consider Stadler Form Oskar Humidifier: If you’re on the hunt for an evaporative humidifier, this one performed well in our testing and released moisture into the air without any mist. Plus, it has a very quiet operation, especially for an evaporative humidifier. However, it’s on the more expensive end of those we tested, and requires you to periodically purchase replacement filters, which will run you about $17 for a two-pack. Raydrop Cool Mist Humidifier: If you’re looking for a quiet and very affordable humidifier, this is a solid option, though it didn’t quite compare to our top picks in its ability to increase humidity levels. We’d suggest it for use either in a small bedroom or near houseplants that thrive in a high-humidity environment. Questions You Might Ask How do humidifiers work? Humidifiers work by adding moisture to the air in the form of mist or water vapor. Their mechanism for doing this can vary depending on whether they are ultrasonic or evaporative and cool mist or warm mist. All humidifiers return moisture to the air to help with dry skin, nasal congestion, temperature control, and more. “Humidifiers can help keep the relative humidity in a comfortable range while helping to keep asthma and allergy triggers at bay,” says Melanie Carver, chief mission officer at the Asthma and Allergy Foundation of America. What are the benefits of using a humidifier? Humidity refers to the amount of water vapor in the air and can have varying effects based on how high or low it is. "High humidity causes the air to feel warmer than it actually is and can cause you to overheat," says Carver. "It also encourages the growth of dust mites and mold, which can trigger asthma and/or allergies. They both thrive in high humidity levels above 50 percent. Low humidity can cause your skin, eyes (including your eyelids), nose, and lips to dry out. It can also result in a dry, sore throat, as well as worsen eczema and asthma." Using a humidifier can help curb these symptoms by introducing moisture into your space. Many parents also choose to purchase a humidifier for a baby’s nursery, because it can help with nasal congestion and provide a soothing environment for sleeping. Humidifiers can also provide a number of benefits for your home, too. Certain house plants thrive in humid conditions. Plus, a constant level of moisture can prevent wood furniture and wall paper from cracking. When are the best times to use a humidifier? Depending on where you live, humidifiers can have benefits in both the summer and winter months.The EPA recommends an indoor humidity level between 30 and 50 percent to prevent the spread of viruses and indoor air pollutants. According to Carver, the humidity levels in your home can be affected by the climate you live in, your home’s air ventilation, and your indoor activities. During the winter months, especially in dry climates, humidity levels can dip below 30 percent—so when temperatures drop, it's the ideal time to run your humidifier. However, constantly running your AC unit during the summer months can remove moisture from the air too, so you may choose to run it year-round. If your humidifier does not feature a humidistat, Carver suggests purchasing a low-cost hygrometer to monitor your home's humidity level. When it comes to time of day, many people choose to run their humidifiers at night. Not only does this provide ambient noise for sleeping, but it also helps alleviate the symptoms of dry air or allergies, including congestion or a dry throat. Can you use tap water in a humidifier? Unless the manufacturer explicitly states to use filtered or distilled water in your humidifier, it's generally OK to use tap water. However, if you're using tap water in an ultrasonic humidifier, and especially if you have hard water, you may notice a fine white dust being expelled out of your humidifier. These are minerals from the tap water that have broken down, leaving behind a white dust once the water evaporates. Although this dust is harmless (unless you are sensitive to dust particles), it can begin to collect on your furniture, walls, and floors. To combat this, you can switch to filtered or distilled water, or opt for an evaporative humidifier, which uses a filter to trap minerals before the water is released into the air. "Using filtered water and changing the water daily will also help prevent mold or bacteria from growing in your humidifier," says Carver. Take Our Word for It This article was written by Melanie Fincher, associate commerce editor for Real Simple with three years of experience writing product reviews and lifestyle content. To come up with this list, we tested 38 humidifiers both in our Lab and in our homes. Melanie spent hours evaluating testing insights, considering factors like setup, effectiveness, design, size, maintenance, and overall value. For expert tips on what to look for in a humidifier, she consulted Melanie Carver, chief mission officer at the Asthma and Allergy Foundation of America. What Is Real Simple Selects? Next to each product on this list, you may have noticed a Real Simple Selects seal of approval. Any product appearing alongside that seal has been vetted by our team—put through tests and graded on its performance to earn a spot on our list. Although we buy most of the products we test, sometimes we do get samples from companies if purchasing a product ourselves isn’t an option. All products go through the same rigorous process, whether they are purchased or sent by the company. Love our recommendations? Check out more products that have earned the Real Simple Selects, from humidifiers to cordless vacuums. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit Sources Real Simple is committed to using high-quality, reputable sources, including peer-reviewed studies, to support the facts in our articles. Read our editorial guidelines to learn more about how we fact check our content for accuracy. Centers for Disease Control and Prevention. What Noises Cause Hearing Loss? Environmental Protection Agency. A Brief Guide to Mold, Moisture and Your Home.